A012119 arctanh(arcsin(arcsinh(x)))=x+2/3!*x^3+32/5!*x^5+1000/7!*x^7+68480/9!*x^9...

1, 2, 32, 1000, 68480, 6561664, 1023602304, 201257787648, 56084851257344, 18730102842232832, 8177799266538749952, 4153222601561664323584, 2616197218964411007008768, 1879040755111699467662589952

Offset

0,2

Links

Table of n, a(n) for n=0..13.

Formula

a(n) ~ (2*n)! / (sinh(sin(1)))^(2*n+1). - Vaclav Kotesovec, Feb 05 2015

Mathematica

nn = 20; Table[(CoefficientList[Series[ArcTanh[ArcSin[ArcSinh[x]]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 05 2015 *)

Crossrefs

Sequence in context: A012233 A321712 A211488 * A282835 A012198 A012114

Adjacent sequences: A012116 A012117 A012118 * A012120 A012121 A012122

Keyword

nonn

Author

Patrick Demichel (patrick.demichel(AT)hp.com)

Status

approved